Yao J L, Kops O, Lu P J, Lu K P
Horticulture and Food Research Institute of New Zealand, Private Bag, 92169 Auckland, New Zealand.
J Biol Chem. 2001 Apr 27;276(17):13517-23. doi: 10.1074/jbc.M007006200. Epub 2000 Dec 15.
The phosphorylation-specific peptidyl prolyl cis/trans isomerase (PPIase) Pin1 in humans and its homologues in yeast and animal species play an important role in cell cycle regulation. These PPIases consist of an NH(2)-terminal WW domain that binds to specific phosphoserine- or phosphothreonine-proline motifs present in a subset of phosphoproteins and a COOH-terminal PPIase domain that specifically isomerizes the phosphorylated serine/threonine-proline peptide bonds. Here, we describe the isolation of MdPin1, a Pin1 homologue from the plant species apple (Malus domestica) and show that it has the same phosphorylation-specific substrate specificity and can be inhibited by juglone in vitro, as is the case for Pin1. A search in the plant expressed sequence tag data bases reveals that the Pin1-type PPIases are present in various plants, and there are multiple genes in one organism, such as soybean (Glycine max) and tomato (Lycopersicon esculentum). Furthermore, all these plant Pin1-type PPIases, including AtPin1 in Arabidopsis thaliana, do not have a WW domain, but all contain a four-amino acid insertion next to the phospho-specific recognition site of the active site. Interestingly, like Pin1, both MdPin1 and AtPin1 are able to rescue the lethal mitotic phenotype of a temperature-sensitive mutation in the Pin1 homologue ESS1/PTF1 gene in Saccharomyces cerevisiae. However, deleting the extra four amino acid residues abolished the ability of AtPin1 to rescue the yeast mutation under non-overexpression conditions, indicating that these extra amino acids may be important for mediating the substrate interaction of plant enzymes. Finally, expression of MdPin1 is tightly associated with cell division both during apple fruit development in vivo and during cell cultures in vitro. These results have demonstrated that phosphorylation-specific PPIases are highly conserved functionally in yeast, animal, and plant species. Furthermore, the experiments suggest that although plant Pin1-type enzymes do not have a WW domain, they may fulfill the same functions as Pin1 and its homologues do in other organisms.
人源磷酸化特异性肽基脯氨酰顺/反异构酶（PPIase）Pin1及其在酵母和动物物种中的同源物在细胞周期调控中发挥重要作用。这些PPIase由一个NH₂端的WW结构域和一个COOH端的PPIase结构域组成，前者可与部分磷酸化蛋白质中存在的特定磷酸丝氨酸或磷酸苏氨酸 - 脯氨酸基序结合，后者则特异性地使磷酸化的丝氨酸/苏氨酸 - 脯氨酸肽键发生异构化。在此，我们描述了从苹果（Malus domestica）这种植物物种中分离出的Pin1同源物MdPin1，并表明它具有与Pin1相同的磷酸化特异性底物特异性，且在体外可被胡桃醌抑制，情况与Pin1相同。在植物表达序列标签数据库中进行搜索发现，Pin1型PPIase存在于多种植物中，并且在一个生物体中存在多个基因，如大豆（Glycine max）和番茄（Lycopersicon esculentum）。此外，所有这些植物Pin1型PPIase，包括拟南芥中的AtPin1，都没有WW结构域，但在活性位点的磷酸特异性识别位点旁边都含有一个四氨基酸插入序列。有趣的是，与Pin1一样，MdPin1和AtPin1都能够挽救酿酒酵母中Pin1同源物ESS1/PTF1基因温度敏感突变的致死性有丝分裂表型。然而，删除额外的四个氨基酸残基消除了AtPin1在非过表达条件下挽救酵母突变的能力，这表明这些额外的氨基酸对于介导植物酶的底物相互作用可能很重要。最后，MdPin1的表达在苹果果实体内发育过程和体外细胞培养过程中都与细胞分裂紧密相关。这些结果表明，磷酸化特异性PPIase在酵母、动物和植物物种中功能上高度保守。此外，实验表明，尽管植物Pin1型酶没有WW结构域，但它们可能履行与Pin1及其在其他生物体中的同源物相同的功能。
